The frontotemporal lobar degeneration risk factor, TMEM106B, regulates lysosomal morphology and function

Area of Science:

• Neuroscience
• Cell Biology
• Genetics

Background:

• Progranulin (PGRN) haploinsufficiency is a key cause of frontotemporal lobar degeneration with ubiquitin (FTLD-U).
• TMEM106B single nucleotide polymorphisms are a risk factor for FTLD-U, particularly in PGRN mutation patients.
• The molecular and cellular roles of TMEM106B in FTLD pathogenesis remain largely unknown.

Purpose of the Study:

• To investigate the cellular localization and function of TMEM106B.
• To elucidate the relationship between TMEM106B and Progranulin (PGRN) in the context of FTLD.
• To understand TMEM106B's contribution to FTLD-U with PGRN mutations.

Main Methods:

• Immunofluorescence to determine TMEM106B localization.
• Cellular assays to assess the impact of TMEM106B expression on lysosomal function and cargo degradation.
• Western blotting to quantify PGRN levels in response to TMEM106B overexpression.

Main Results:

• TMEM106B localizes to late endosome/lysosome compartments.
• TMEM106B expression alters lysosome morphology and delays endocytic cargo degradation.
• Overexpression of TMEM106B leads to increased PGRN levels, potentially by inhibiting lysosomal degradation.

Conclusions:

• TMEM106B plays a role in regulating lysosomal function and the endolysosomal pathway.
• TMEM106B may contribute to FTLD-U pathogenesis by modulating PGRN levels.
• These findings provide novel insights into the cellular mechanisms underlying FTLD-U.